During winter meetings we have been emphasizing the importance of controlling Palmer Amaranth, one of the most dangerous weeds for Ohio agriculture. It is one of the fastest spreading weeds that is trying to get a foothold in the Corn Belt. It can spread like wild fire unless stopped in its tracks. Check out the facts below:
• Palmer Amaranth is an annual broad leaf and is related to other Amaranth species like Pigweed, Waterhemp, and Redroot.
• It grows faster than other pigweed species and can grow 2-3 inches per day. Some studies have reported it can reduce corn and soybean yields by 70-80%, if not controlled.
• Palmer Amaranth has already caused a lot of problems in the South and recent reports from Kentucky indicate it is marching north and east, spreading into Illinois, Indiana, Michigan and Ohio.
• Each Palmer Amaranth plant can produce up to one million seeds. The heads containing the seed can be more than 20 inches long and each plant can produce multiple seed heads.
• We need an aggressive management approach to control the spread of this weed to protect our crops.
• Now that most of the crops are planted, we must pay attention to weed control, especially, if Palmer Amaranth is suspected. As with all weeds, it is easier to kill them when they are small. For me, the only good weed is a dead weed.
• Most of the Palmer Amaranths populations are resistant to glyphosate and ALS herbicides, although some atrazine resistant populations have also been found.
• Controlling glyphosate and ALS resistant populations of Palmer Amaranth is going to be tough.
Some of the strategies recommended by Purdue scientists are:
1. Rotate crops and herbicides.
2. Use suitable herbicides.
3. Deep tillage to bury seeds of Palmer Amaranth.
4. Use crimped cereal rye grass as cover crop.
5. Keep drainage ditches and field borders clean.